what compression are you running? those cams are spec'd to run a hell of a lot of lift at TDC which suggests they will be giving very peaky power, possibly even putting the theoretical peak power at higher revs than you are using. where's your rev limit? got a dyno graph?

I'd say the cams are excessive for the rest of the spec then, you'd need to be up around 12.5:1 really. The trouble is, you're going to need upgrades to the cam rocker gear before you can raise the limit any further, you'll get air in the hydraulic lifters above that limiter. Dialing in the cams for less lift at TDC should improve the situation with your current spec

Not sure if you've seen before, but someone previously posted a reply to a question on rough build spec he got from one of the s1600 project engineers. Interesting to see if they'd field more specific questions?

I wrote an email to renault sport some years ago with this questions and got an answer.

"Oliver,

AS enhenced the Renault K4M engine is, to tune it from 110 HP to 220 HP is a big challenge !!

The FIA regulation on the S1600 categorie concerning the engine relies on the following statements:

- single throttle box with a max diameter of 60 mm
- max engine revs : 9000 RPM
- to keep the original valves diameter
- no modification on the oil and water pump
- Compression ratio : The maximum compression ratio is 13/1.
- Valve timing and valve lift : Variable systems are prohibited.
- Variable geometry intake and exhaust manifolds are prohibited
- titanium and magnesium are prohibited.
- The head intake and exhaust holes can be increased in dimension by only 4%

What we have doneon the engine:

- The K4M bloc has not been modified (nor bore and stroke)
- the crankshaft is extracted from the Renault K9K standard engine !!!
- the crankshaft bearings are specific for heavy duty
- the conrods are specific (machined from solid with Renault K9K bearings)
- the pistons (specific shape) are aluminium forged
- Intake and exhaust ducts of the cylinder head have been polished to improve their permeability.
- Of course the camshafts are specific (machined from solid for the rigidity), also the valves and springs.
- Because of the high engine max rev, we have redesign the rockers and hydraulic bumps but keeping the same concept (rocker with bearing and spherical contact between the rocker and the bump; the hydraulic height adjustment of the rocker bump has been cancelled to prevent the bump from pumping up).
- We have particularly paid attention to the acoustic adjustement between the air intake manifold and the exhaust line in order to optimise the compromise of the torque diagram (for tarmac and gravel use)
- the flywheel (steel machined from solid) has been lightened to reduce inertia.
- The ECU (specific to racing) is from Magneti marelli (MF4M)

Because of the modern design of the Renault K4M engine, we are confident in having one of the very best S1600 engine today !!

Sorry, but we don't have any picture of the engine at the moment.
Maybe in a few days.

In other words, put again more sporty cams inside, higher compression ratio, shorter and wider íntake manifold, head work, exhaust with more lower back pressure and you will have it. But for this the engine needs to rev up higher which requests additional modifications from mecanical side as described. But I think such an engine isn´t drivable under public road conditions as you won´t have much torque below 4000 rpm...

I am a big fan of Rallycross since 1988 and since then have always loved the cars, brands, tuners and drivers active in the sport. I have recently bought a Twingo RS which has a revised K4M engine, the K4M RS, which has variable valve timing which isn't allowed in the Super 1600 (I suppose). Before buying it I had a chat with long time Renault driver Marcel Snoeijers, because the 133 bhp seems a bit low and I was hoping that 160-180 would be possible on throttle bodies. He told me that the car was not the most easiest to get serious and reliable power out of it... So in the end he bought a Sodemo engine, which isn't cheap and certainly not suited for the road! I am therefore very interested how your story continues, because you are kinda running the ultimate road spec... Have you already tried the higher compression ratio that Sideways Danny has suggested? Does you engine also have the Sodemo strengthening kit? And is it proven to be reliable? Are the conrods also from Wossner? And I am very interesting to see how the torque curve and output is, since throttle bodies usually have a stunning midrange and guessing your engines is over 70 bhp short on Bakkerud Championship winning Clio, the torque should at least be more useable (for the road that is)? Oh, Marcel Snoeijer told me his engine could run a potential 10.000 rpm! Blimey! And the lifters and something that controls the cam are a difficult part.

Not sure if you've seen before, but someone previously posted a reply to a question on rough build spec he got from one of the s1600 project engineers. Interesting to see if they'd field more specific questions?

Click to expand...

That is so cool! Does this mean the first Super 1600's where build by Renault? Are the latest Evolutions by Sodemo? So the crankshaft is extracted from the 1.5 DCi engine, I have seen Diesel blocks used before in Rallycross, but mostly this mend using the complete short block mated to a petrol head, not just the crankshaft, interesting stuff!
Also interesting to see that the Super 1600 remains their original valve diameter and no aluminum flywheel and such.

Can anyone also tell if the K4M or K4M RS engine have oil squirt piston cooling? And any forged items as standard?

I am a big fan of Rallycross since 1988 and since then have always loved the cars, brands, tuners and drivers active in the sport. I have recently bought a Twingo RS which has a revised K4M engine, the K4M RS, which has variable valve timing which isn't allowed in the Super 1600 (I suppose). Before buying it I had a chat with long time Renault driver Marcel Snoeijers, because the 133 bhp seems a bit low and I was hoping that 160-180 would be possible on throttle bodies. He told me that the car was not the most easiest to get serious and reliable power out of it... So in the end he bought a Sodemo engine, which isn't cheap and certainly not suited for the road! I am therefore very interested how your story continues, because you are kinda running the ultimate road spec... Have you already tried the higher compression ratio that Sideways Danny has suggested? Does you engine also have the Sodemo strengthening kit? And is it proven to be reliable? Are the conrods also from Wossner? And I am very interesting to see how the torque curve and output is, since throttle bodies usually have a stunning midrange and guessing your engines is over 70 bhp short on Bakkerud Championship winning Clio, the torque should at least be more useable (for the road that is)? Oh, Marcel Snoeijer told me his engine could run a potential 10.000 rpm! Blimey! And the lifters and something that controls the cam are a difficult part.

Click to expand...

Hi mate,

Following your post on Twingo133 I have replied, very sorry for not replying sooner.